Fig. 3.

ARP/actin interactions. (A) Schematic representation of actin/ARP domains within actin filaments (orange) (31). (B) Domain organization within the Arp2/3 complex (green) (19). Arp2 domains 1 and 2 are not visible in the Arp2/3 crystal structure but are shown here in positions inferred from the overall actin fold. (C) Arp7–Arp9 domain organization. Note that residues from Arp7 domain 4 interact with Arp9 residues forming an extended loop from domain 3, although this interaction is not apparent in the stylized representation that depicts spheres centered on domains. (D) Front view of Arp7, with surface contacting Arp9 colored purple. (E) Back view of Arp9, with surface contacting Arp7 colored yellow.